Foldable blank and carton



Feb. 25, 1964 1.. E. LA BOMBARD FOLDABLE BLANK AND CARTON Original Filed June 12, 195.8

2 Sheets-Sheet 1 D mR M MM B A L E N O E L ATTORNEY Feb. 25, 1964 E. LA BOMBARD 3,122,300

FOLDABLE BLANK AND CARTON Original File d June 12, 1958 2 Sheets-SheetQ Fig. ll

31 83 Fig. I4 261 8| INVENTOR L EON E. LABOMBARD 8'4 g BY 7 M ATTORNEY United States Patent 3,122,301) FOLDABLE BLAYK AND CARTGN Leon E. La Bernhard, Nashua, N.H., assignor to The International Paper Box Machine Company, Nashua, N.H., a corporation of New Hampshire Original application June 12., 1958, Ser. No. 741,513, new Patent No. 3,039,372, dated June 19, 1962. Divided and this application Dec. 11, 1959, Ser. No. 676

4 Claims. (Cl. 22937) This invention relates to boxes and blanks of paperboard capable of accurate, true folding on high speed folding machines.

It has long been customary to impress creases in paper material to create foldable box blanks, the creaser dividing the blanks into wall panels, flaps or tabs in cooperation with slits, cut-outs and the like. When the paperboard is relatively thin, such creases can be formed by well known apparatus and the blanks will usually fold accurately on the crease lines at low or high speed. When the paperboard is relatively thick, for example, laminated board or corrugated board, however, ordinary creasing apparatus tends to be less effective and the resulting blanks tend to fold improperly, especially at high speed.

An object of the invention is to provide a foldable box blank or a box of relatively thick paperboard in which the wall panel fold lines are formed by superposed layers of stretched fibres bounded on each opposite side by shoulde's of unstretched fibres and undeformed paper stock.

Another object of the invention is to provide a box blank of corrugated paperboard with wall panel fold lines so sharply defined as to assure 180 folding of selected panels in exact alignment even under the twisting infiuence of high speed folder belts.

Other objects and advantages of the invention will be apparent from the claims, the description of the drawings and from the drawings.

The machine and the method of the invention are claimed in my copending application, Serial No. 741,513, filed June 12, 1958, now Patent No. 3,039,372, granted June 19, 1962, of which this application is a division, and the disclosure thereof is retained in this application for a better understanding or" the manner in which the fold achieved thereby differs from the prior art.

FIG. 1 is a side elevation of creasing mechanism suitable for creating the flat foldable blank and carton of the invention.

FIG. 2 is a sectional view on line 2-2 of FIG. 1.

PEG. 2A is a View similar to FIG. 2 of a modification.

FIGS. 3, 4 and 5 are enlarged, fragmentary views showing the creasim action creating the compound crease of the invention.

FIG. 6 is a perspective view of a box blank in accordance with the invention.

FIG. 7 is a view similar to FIG. 5 of the crease impressed in one type of corrugated paperboard by the mechanism.

PEG. 8 is a View similar to FIG. 7 showing a blank being folded on the compound crease of this invention.

FIG. 9 is a view sLnilar to FIG. 7 of a corner of a box of corrugated paperboard made in accordance with the invention.

FIG. 10 is a View similar to FIG. 7 of a corner of a fiat tubular collapsed box of corrugated paperboard made in accordance with the invention.

F163. l1, 12, 13 and 14 are views similar to FIGS. 7, 8, 9 and 19 but with the blank and boxes made of laminated paperboard in accordance with the invention.

As shown in FIGS. 1 and 2 the creasing apparatus for making a blank with the compound crease of the invention includes opposed pairs of creaser bars 20 and 21, each pair arranged to impress a crease in a sheet or web of paperboard positioned or passing therebetween.

he bars 2% and 21 may be mounted on suitable mechauism, forming no part of this invention, for causing the bars to rotate in parallelism toward and away from the material or stock to be creased. For example, the mechanism of the above mentioned Smith and Knowlton patents; or the mechanism described and illustrated in my patent application, Serial No. 709,977, filed January 20, 1958, now Patent No. 2,949,666, granted August 16, 1960, is satisfactory for the purpose, or any other similar apparatus well known in the prior art.

The creaser bars 29 and 21 are mounted to rotate in parallelism on eccentric driving members such as 22 and 23 and are normally spaced apart to admit the paperboard. It will be understood that the paperboard to be creased in the device of this invention is usually relatively thick, resistant to creasing and likely to erase a crease made therein. it may be of corrugated paperboard such as shown in FIGS. 3 to 10 or of paperboard of the pressed or laminated type such as shown in FIGS. 11-14. A typical material is illustrated in FIG. 6 in the form of a simplified box blank 24- of corrugated paperboard in which the closure flaps are not shown. The blank 24 includes the wall panels 25, 26, 27 and 28 and the glue flap 29 and may be formed into a fiat, tubular, collapsed box in a manner well known in the trade by fold belts or the like. Unless the fold lines 31, 32, 33 and 34 are well defined in the corrugated material, the blank will resist the folding action of the fold belts and the panels may fold inaccurately. In a collapsed box at least two of the folds, for example on lines 31. and 33, will be at whereby suflicient material must be displaced or crushed along the inside of the fold to keep the outside of the fold from fracturing or tearing.

The creaser bar 21 is provided with a single creasing blade 36 which is preferably of fiat elongated material such as metal. The base 37 of blade 36 is detachably fixed in slot 38 of bar 21 by set screws 39 or other suitable means and the blade may be of any desired length depending on the length of the creases desired. The free terminal edge 41 of blade 36 is rounded slightly to avoid cutting the paper stock and the height of the blade above.

the face 42 of the bar 21 is critical. Contrary to the teachings of the prior art, the face 42 of the bar 21 of this invention performs no camming action and at no tirne does it exert pressure on the material being creased or on the parts of the opposite creaser bar. As best shown in FIGS. 35 the material to be creased is supported adjacent the creaser blades 21 and 22 by the elongated rigid support rods 43 and 44 which are laterally spaced from the creasing area. The blade 36 is adjusted at such height above face 42 as to have a substantially greater effective height than the height of the opposite double blades as best shown in FIG. 2. Thus the crease is impressed with the double blades overlapping the single blade but never crushing the material against a rigid, immovable surface such as the face 42.

The creaser bar 26 is provided with a pair of identical creaser blades 46 and 47, of flat, elongated material such as metal, each having a rounded tip 48 or 49 similar to tip 41. The bar 20 is cut away on each opposite side to form a pair of tapered recesses 51 and 52, separated by the tapered central portion 53, the portion 53 extending between the bases 54 and 55 of the blades 46 and 47. A pair of cover plates 56 and 57 are detachably fixed by bolts such as 58 to each opposite side of the bar 29 as shown. The blades 45 and 47 are perforated at 69 and 61 to receive the pivot pins 62 and the portion 53 is provided with a series of holes such as 63 for coil springs such as 64. The double blades 46 and 47 are coextensive in length with the single blade 36, spaced laterally on each opposite side of blade 36 and of a predetermined height above the faces 65 and 66 of plates 56 and 57 which is substantially less than the corresponding height of blade 36.

A series of set screws such as 67 and 68 are threaded in cover plates 55 and 57 to permit the blades 46 and 47 to be teed in at various an les and to constitute an adjustable stop for controlling the maximum divergence of the blades. The tips 48 and of the double blades are free to be moved inwardly toward each other by the pivoting of the blades on the pins 62 against the opposition of the coil springs 64 which constitute the return means for urging the blades toward their position of maximum divergence. It will be obvious that with no sheet-like material between the blades 36, 46 and 47 the creaser bars 2% and 21 may approach each other with no pinching action whatever on the part of the double blades. The bars are of course so set that they rotate in parallelism without actually touching each other, the point of closest approach being indicated in FIG. 5.

ln PiGS. 35 the operation or" the creasing apparatus for making a blank with the compound crease of this invention is illustrated as applied to forming a crease in corrugated paperboard although it will be understood that the operation is the same with pressed or laminated paperboard. The corrugated material selected for illustration is of the type having an inner liner 79, a fluted section Si and an outer liner 7%) known as Flute double face and the upper and lower tips such as 71 and 72 are connected to the liners by an adhesive film such as 73 or 74.

As shown in FIG. 3 the single blade 36 is approaching the space between the double blades 46 and 47 with the corrugated material, for example, the box blank 24, supported on the rods 43 and 44. The creaser bars, being rotatably mounted, are advancing in the direction of advance of the blanks as they approach each other and there may be a plurality of sets of such bars simultaneously formin" creases along the fold lines 31, 32, 33 and 34 of the each successive blank 24. It should be noted that the rounded tips 48 and 49 of each blade 46 or 47 first impress a shallow furrow such as at 75 and 76 in the inner liner, or top laminations, of the material and thereby become seated and frictionally adhered in the material. Despite any initial toe-in of the blades 45 and 47, the toein is not increased in this first stage of the crease.

As shown in FIG. 4 the continued pressure and approach of the blades 46 and 47 toward the blade 36, increases the depth of the furrows 75 and 76 and creates an opposite depression 77 in the lower liner, or lower laminations, of the material. The rounded tips 48 and 49 being firmly seated in the furrows 75 and 76 they have created do not slip and wipe across the material but are drawn toward each other, and toward the sides of blade 36 in a pinching action as the double blades pivot inwardly within the recesses 51 52. At this point an inwardly projecting ridge 7% is commencing to form between the Iurrows 75 and 76 and the fibers in the layers, or laminations, between blades to and 47 are commencing to be stretched.

ln FlG. the final crease is shown with the double blades 46 and 47 overlapping the blade 36 and drawn tightly toward the sides of blade 36 to stretch the fibers 1n the layers in progressively increasing amounts from bottom to top. The adhesion between the layers of stretched fibers is destroyed in this operation so that the layers or lannnations become separated from each other. However, on each opposite side of the crease there has been no streaching of fibres and no destruction of the adhesion of the layers of the material because the double blades are moved only by and with the material being formed into an inwardly projecting ridge therebetween.

Upon release of the material such as blank 24, and separation of the creaser bars 2% and 21 the crease impressed in the material is as shown in FIG. 7 for corrugated board and in FIG. 11 for pressed board. In the corrugated material of FIGS. 6 and 7 the wall panels are divided by the compound creases shown which define the fold lines 31, 32, 33 and 34- and are characterized by a narrow strip of stretched fibres in the outer liner 7%, created by the depression 77, a narrow ridge 82 of stretched fibres in the inner liner 79, ridge 32 overlying, but spaced from strip 31, the pair of narrow furrows and 76 formed of stretched fibres in inner liner 7, and the narrow portion 33 in the fluted section fill, formed of stretched fibres. The compound crease of this invention is characterized by a beveled Zone of pre-stretched fibres, widest in the inner layers, or liner 79, between the outer bounds of the furrows 75 and 76, less wide in the intermediate layer, or fluted section 30 and narrowest in the outer layers, or liner 7b, between the bounds of the strip 81. Any adhesion between the flute tips of section 8% and the liners 79 and '79 has been destroyed by the stretching of the layers over the blade 36. Each compound crease is further characterized by a pair of parallel strips 84 and on each opposite side of the beveled zone of stretched fibres which I call shoulders and which are uncompressed, unstretched and undeforrned by the double blades 46 and 47. Because the compound crease is so bounded, a shoulder such as 84 presents a firm beveled barrier to the ridge 82 and portion 83 as a panel such as 25 is upfolded on line 31 as shown in FlG. 8. The strip 81, on the other hand, gradually flattens into taut condition during the upfolding and cannot twist out of accurate longitudinal alignment as might be the case if the material of beveled shoulder 84 was crushed, deformed or otherwise made too flexible. In practice, a straight line marked along the longitudinal centre line of the depression 77 remains exactly centred as the depression is erased and the strip 81 becomes taut during a or fold.

When the ridge 82 and portion 83 are barred from further angular movement by the shoulder 84, the further folding of the panel 25 takes place on the furrow 76 as a pivot zone until the fold is at 90 as shown in FIG. 9. A completed and erected box of rectangular cross section such as indicated at 87 will thus have four corners, each with the compound crease shown in FIG. 9 and each char acterized by a pair of beveled undeformed shoulders such as 84 and 35 which retain the original integrity of the material and bound the stretched fibrous layers of the fold line to accurately define the fold.

A fiat, tubular, cells sed box of corrugated paperboard such as indicated at $3 will have two alternate fold lines such as 31 and 33 creased as in FIG. 7 and the ther two alternate fold lines such as 32 and 34 creased and folded through an angle of 180 as shown in FIG. 10. The furrow 77 in strip 81 is erased and the material thereof is stretched taut on the outside of the 180 fold lines while the ridge 82 and portion 83 are compressed by the opposite beveled shoulders 84 and 85 with identical pressure, thereby maintaining the longitudinal alignment of the fold. The inherent resiliency of the bowed portions 82 and 83 keeps the portion 31 taut and the shoulders 84 and 85 in correct position thus eliminating looseness, excessive flexibility or flabbiness at the fold line and assuring that the panels or" the collapsed box 88 are squaredup and tend to remain squared-up.

In FIG. 11 the creasing apparatus has been applied to laminated, or pressed paperboard 96, for example. in creating a box blank such as 24 to be formed into boxes such as 87 or 83. As shown, the single blade 36 has created a depression 91 in the outer laminations and the double blades 46 and 47 have created a pair of shallow furrows 92 and 93 in the inner laminations. The board 90 is of course formed of layers of paper and layers of adhesive all bonded into a relatively rigid and uncompressible mass but the blades of this invention are capable V of impressing the crease shown in such material under the same pressures as are used for corrugated material.

The resulting compound crease is formed by a plurality of overlying layers of stretched fibres indicated generally at 94, 95 and 96, the adhesion between the layers being destroyed and the layers separated from each other. The layers 94, 95 and 96 are of progressively increased bowed formation and of progressively increased width from the outer layer, or lamination to the inner layer or lamination, to form a bevelled zone of stretched fibres in the inner, intermediate and outer layers of the paperboard. The compound crease is bounded by the beveled shoulders 97 and 98 on each opposite side thereof which are similar to shoulders 84 and 85 and are made up of unstretched fibres and unbowed unseparated layers of fibres.

As shown in FIG. 13, the shoulders 97 and 98 maintain the right angular corners of a rectangular box such as 99, a portion of which is illustrated, in the same manner as indicated in FIG. 9 for corrugated material.

As shown in FIG. 13, the outer layers or laminations 94 are stretched taut while the intermediate layers 95 and the outer layers 96 are bowed into a plurality of separated, ridges of stretched fibres which can be compressed by shoulders 97 and 93 when a flat, tubular collapsed box 100 is formed by alternate folds of 180 each.

In addition to the fact that the creaser blades are unopposed by any other surface and therefore cannot crush the layers of the paper stock, it should be noted that the double blades do not press on the sides of the furrows for forcing the layers to bow or buckle to a height above the single blade. Instead the double blades stretch the fibrous layers or liners over the edge, and along the sides, of the single blade to enable the outer layers or liner to yield without strain or fracture during 180 folding. The result ng compound crease is actually a double hinge connection between adjoining panels, each being capable of 90 of fold along the lines of the pair of furrows formed by the double blades.

The lateral spacing between the tips 4-8 and 49 of blades 46 and 47 is critical in that it is adjusted by means of the set screws 67 and 68 in accordance with the thickness of the paper stock material. If the material is thin the blades are closely spaced and if the material is thick the blades are widely spaced.

As shown in FIG. 2A the double blades may be in the form of the pair of blades 101 and 102 of inherently flexible resilient material such as spring metal, each fixed by screws 103 to a creaser bar 104.

I claim:

1. A foldable box blank of corrugated paperboard of the type having an inner liner, an intermediate fluted layer section and an outer liner, said blank being divided into a plurality of wall panels by a plurality of impressed, wall, fold creases, each said wall fold crease comprising a single, narrow depression forming a strip of stretched fibres in the outer liner, a narrow ridge of stretched fibres in the inner liner, said narrow ridge overlying, but spaced from, said narrow depression, a pair of narrow depressions overlapping said first depression and formed of stretched fibres in said inner liner, each on an opposite side of said narrow ridge and a narrow portion of stretched fibres in said fluted layer section between said narrow depression and said narrow ridge, each said wall panel fold crease being free of crushed fibres and being bounded on each opposite side thereof by beveled shoulders of uncrushed, unstretched fibres.

2. A combination as specified in claim 1 wherein the flutes of said intermediate fluted layer section extend parallel to said impressed wall fold creases and the tips of the flutes within said compound crease are free of adhesion to the adjacent liner.

3. A box of corrugated paperboard of the type having an inner liner, an intermediate fluted layer section and an outer liner, said box being of rectangular cross section and having a plurality of wall panels divided by compound creases, each said compound crease comprising a single, taut strip of pre-stretched fibres in the outer liner; a narrow ridge of pre-stretched fibres in the inner liner, said narrow ridge overlying, but spaced from, said taut strip; a pair of narrow depressions formed of pre-stretched fibres in said inner liner, each on an opposite side of said narrow ridge and a narrow portion of pre-stretched fibres in said fluted layer section between said taut strip and said narrow ridge, each said compound crease being free of crushed fibres and being bounded on each opposite side thereof by beveled shoulders of uncrushed, unstretched fibres.

4. A foldable box blank of corrugated paperboard of the type having an inner liner, an intermediate fluted layer section and an outer liner, said blank being divided into a plurality of wall panels by a plurality of impressed, wall, fold creases, each said wall fold crease comprising a single, narrow depression forming a strip of stretched fibres in the outer liner, a narrow ridge of stretched fibres in the inner liner, said narrow ridge overlying, but spaced from, said narrow depression, a pair of narrow depressions, approaching substantially to overlapping relation with said first depression and formed of stretched fibres in said inner liner, each on an opposite side of said narrow ridge and a narrow portion of stretched fibres in said fluted layer section between said narrow depression and said narrow ridge, each said wall panel fold crease being free of crushed fibres and being bounded on each opposite side thereof by beveled shoulders of uncrushed unstretched fibres.

References Cited in the file of this patent UNITED STATES PATENTS 247,320 Dean Sept. 20, 1881 1,708,700 Maier Apr. 9, 1929 2,067,754 Decker Jan. 12, 1937 2,382,891 McCormick Aug. 14, 1945 2,612,305 Klasing et al Sept. 30, 1952 2,949,151 Goldstein Aug. 16, 1960 

1. A FOLDABLE BOX BLANK OF CORRUGATED PAPERBOARD OF THE TYPE HAVING AN INNER LINER, AN INTERMEDIATE FLUTED LAYER SECTION AND AN OUTER LINER, SAID BLANK BEING DIVIDED INTO A PLURALITY OF WALL PANELS BY A PLURALITY OF IMPRESSED, WALL, FOLD CREASES, EACH SAID WALL FOLD CREASE COMPRISING A SINGLE, NARROW DEPRESSION FORMING A STRIP OF STRETCHED FIBRES IN THE OUTER LINER, A NARROW RIDGE OF STRETCHED FIBRES IN THE INNER LINER, SAID NARROW RIDGE OVERLYING, BUT SPACED FROM, SAID NARROW DEPRESSION, A PAIR OF NARROW DEPRESSIONS OVERLAPPING SAID FIRST DEPRESSION AND FORMED OF STRETCHED FIBRES IN SAID INNER LINER, EACH ON AN OPPOSITE SIDE OF SAID NARROW RIDGE AND A NARROW PORTION OF STRETCHED FIBRES IN SAID FLUTED LAYER SECTION BETWEEN SAID NARROW DEPRESSION AND SAID NARROW RIDGE, EACH SAID WALL PANEL FOLD CREASE BEING FREE OF CRUSHED FIBRES AND BEING BOUNDED ON EACH OPPOSITE SIDE THEREOF BY BEVELED SHOULDERS OF UNCRUSHED, UNSTRETCHED FIBRES. 